Process of making sulfuric anhydrid.



PATENTED JAN. 9, 1906.

R. KNIETSOH.

PROCESS OF MAKING SULFURIO ANHYDRID.

APPLICATION FILED SEPT. 24, 1901.

INVEN TOR 7W A44 ATTORNEM [at 1/66 whom it may concern:

- UNITED STATES,

PATENT oFE- CE.

RuDoLF KNIETSOH, OF LUDWIGSHAFEN-QN-THE-IRHHfIE, GERMANY, ASSIGNOR, 'BY EsNEiAssIGNMENTs; To GENERAL CHEMICAL COMPANY,- A, CORPORATION OFREWg-YORK.

,PBocEssjoF'MAKm'e SULFURIC ANHYDIRIID.

7 Be it known that I, RUDOLF KNIETSCH,

,doctorof philosophy nd chemist, a subject of the King of Prussia, German Emperor, re siding at Ludwigshafen-on-the-Rhine, in the Kingdom of Bavaria,Germany, have invented new and useful Improvements in-the Manufacture of Sulfuric Anh'ydrid, ofv which the following is aspe'cification;

After my iscovery of the process de-.

, scribed in my Patents No. 652,119, dated- June 19, 1900, and No, 692,018, dated January 28, 1902, whereby a substantially quantitative production "of SO was for thefirst time accomplished by the contact method, it seemed fromall analogyinthe prior art to, be incapable of further improvement, and. certainl no waywas apparent by which the materia s employed could be 'economized Without impairing the primary obj ect-..a substantially quantitative yield; Nevertheless,

I have discovered an improvement on said process. the resultaof which is to combine with the substantially quantitative yield of said processa saving of a large portion, ap-

' proximatel fift per cent, of the contact material. 'ot er words, I have discovered that if the gas .containingsulfur dioxid and.

- oxygen (exemplifiedinsaid Patent N 0.652, 119 by a mixture of gases containing about twelve per cent. by volume, of sulfur dioxid and a similar quantity of oxygen, thb'alanceof the volume consisting, substantially, of an indifferent gas, such as nitrogen) is subjected to a succession of treatments by the process described in my said Patent No; 652,119

. with an intermediate removal of the formed S0 a conversion which is from ninety-six to ninety nine er cent. of that theoretically possible may e produced by the use of about fty er cent. atiniied asbestos less than -woul be necessary to accomplish a similar conversion by one treatment of said process. a

- In carrying out my process I emp 0y two or more contact chambers operating according to said process, each 0 which may be constructed as described in mys'aid Patent No. 692,01 8', and between every two of these I V interpose 1n the course 'of the-gas passing from one tothe other an absorbing apparatus for the S0 preferably constructed i e that 3 Specification, of Letters Patent. Application 1011 s ienibarm, 1901. Serial 110-76332.

described in said Patent Nos 692,018..'

In #case. two contact-chamibers are em- Patented Jan. 9, 1906.

plo ed the amount of contact material in eac of them will be only aboutone quarter the amount heretofore used in'operatlngunder my said patents. The mixture of puri, fied S0 gas with oxygen is passed through the first of these contact-chambers and-is thereinsubjected to the catalytic action,

'while the excess of heat, due to the reaction,

is removed-from the contents of said chamtheSO L'. Thusthe gas escaping from said first contact-chamber consists of unconverted S0 and oxygen mixedwith $0,. This gas then) passes through said a'bsorbng apparatus, wherein the SQ, already formed is 'ber. A portion of the gas is thus converted into S0 while avoiding, the decomposition of converted into S0 by the same process as that a plied in the first contact-chamber. TheS 3 thus formed passes then into a second absorbing apparatus, wherein it isseparated-from any waste gases that may be mixed with it. I

'In the accompanying drawing I have shown an apparatus containingtwo contact structures in each of which M is an inclosure I which may'consist of brickwork or other suitable material. ,Jy I

R representsthe contact-chambers, (shown in the-form of tubes) supported at one end by the tube-plate W and at the other end by i the tube-plate W. a

S is "an alr-passage surrounding the contact-tubes from end to end and having inlets 'n-at one end and outlets L, regulated by the adjustable dampers l. v

' it represents means of heating the air-currents at 'or near the entrance to the passage S, which heating means should bev capable of prompt-extinction, lighting, and regulation, such as gas-flames or the equivalents.

71; represents similar heating means located about midway the passage S. These heating means are shown as situated oppos1te the ,lower and upper endsof the contact material I), which extends substantially half the length of the tubes R'. '7 D and D are covers inclosing the opposite ends of each'series of tubes.

' O is a pipe leading to the apparatus from a source ofmixture of gas containing sulfur c is the exit for the roduct of the first apparatus, which exten s through the cooler O and empties into the absorber A beneath the surface of an absorbing body'of sulfuric acid contained therein, which absorbs the SO,, and

permits the remainder of the gases to pass onward-through the pipe 0 into the second part of the apparatus. The product of the second part of the apparatus escapes through the pipe 0, which passesithrough the cooler C and empties into the absorber A beneath the surface of an absorbing bod of sulfuric acid therein, which absorbs the O and permits the waste gases to escape through the pipe O This process, while allowin of the production of as good a yield of su furic anhydrid as is obtained under the process of my said patents, permits of more than half of the platinum, and in some cases as much as seventy per cent. thereof, being dispensed with. The importance of this will be apparent from the fact that I have found that in operating under my said Letters Patent without the present improvement a relatively small amount of platinum contact material sufr ficed to convert from seventy to ninety per cent. of the sulfurous acid into sulfuric anhydrid, but that to further increase the-percentage of conversion an inordinately large quantity of platinum was necessary. If, for example, with one hundred parts of platinum a total conversion of ninety-seven per cent. was obtained, the production .of the first eighty per cent. of the sulfuric anhydrid only required aboutfifteen arts of the total platinum employed, while or the remaining seventeen per cent. a further eighty-five parts of the platinum was necessary.

My process can be varied by dividing it into more than two contactsfor example, three contactsthus still further increasing the total conversion; but as a general rule two contacts will be found sufficient for practical dpurposes, and the first conversion shoul preferably amount to from eight to ninety per cent. In this manner a sul ric anhydrid or sulfuric acid can be '4 obtained soaee o from the first operation, which does not con tain so much sulfuric acid as to make it unfit for technical pur oses.

Having thus claim as new and desire to secure byLetters Patent..

1. The process of manufacturing sulfuric escribed my invention, I

anhydrid which consists in passing sulfurousacid gas and oxygen over contact substance containing platinum, interrupting the process when the conversion has been partially effected, removing sulfuric anhydrid formed and subjectin the unconverted gases thus freed from su furic anhydrid to further action of contact substance containing platinum.

2.'The process of manufacturing sulfuric anhydrid which consistsin passing sulfurousacid gas and oxygen over contact substance containing platinum which is subjected to a regulated cooling so as to remove the excess 'of heat due to the reaction,.interrupting the tact substance containing platinum, inter-' rupting the-process when a portion of the re- .maining sulfur dioxid has been converted into sulfuric anhydrid, removing sulfuric anhydrid formed and subjecting the remaining unconverted gases to further action of contact substance containing platinum. I

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses.

RUDOLF KNIETSCH. v Witnesses:

PAUL SEIDEL, JoHN L. HEINKE. 

